This invention relates to a connector or coupling device, and in particular to a coupling device adapted for use with helically wound rods for a sewer cleaning device.
The difficulties in coupling lengths of sewer-cleaning rods together, and the dire consequences should the coupling device fail, have long been known.
A number of connectors for lengths of sewer-cleaning rod have been devised, but all have drawbacks, such as not locking positively, being difficult to assemble and disassemble, including loose parts which are easily lost, or requiring special tools for assembly and disassembly.
An example of a previously-known sewer rod coupling is Kollmann, U.S. Pat. No. 2,755,115, in which a male portion having an enlarged head and a neck extending transverse of the axis of the sewer-cleaning rod is slipped into a corresponding transverse slot in a female portion. A spring-loaded, axially extending locking pin extends through the end of the male portion and into the female portion. The parts are separated by inserting a tool into a transverse bore in the female part to retract the pin.
Another example is Kollmann, U.S. Pat. No. 2,278,324 in which a male portion of the connector includes a shoulder extending transverse of the axis of the sewer-cleaning rod. The shoulder is slipped into a corresponding transverse slot in a female portion, and a locking bolt extending at right angles to both the shoulder and the axis of the sewer-cleaning rod locks the two parts together. The bolt is held in place by a spring between its head and the shoulder and by a U-shaped washer in a groove at the distal end of the bolt. To separate the parts, the U-shaped washer is removed from its groove, and the bolt and spring are removed.
A commonly utilized connector incorporates features of both these patents: a male portion having a transverse head and neck portion is slipped into a corresponding slot on a female portion, to hold the sections of rod to which they are attached against axial separation. A locking pin, corresponding to the locking bolt of Kollmann U.S. Pat. No. 2,278,324, prevents the two halves of the coupling from being slipped apart transversely. The locking pin is held frictionally in a bore through the female part and extends through a slot in the neck of the male part. Releasing the parts requires driving the locking pin from the bore.